Louis XIV of France, also known as the Sun King, is one of the most important figures in European history. An encrypted letter he wrote in 1693 has never been deciphered.
According to a recent BBC article, a British student has broken a “religious code” from the 18th century. What is behind it?
In 2017 I blogged about a Pigpen ciphertext that had been discovered in the London suburb of Croydon. This cryptogram is still unsolved.
In 1905 and 1906 a man named Harry sent a series of encrypted postcards to a friend named Charlie. Can a reader decipher these messages?
Yesterday I visited a great crypto exhibition hosted by the German Armed Forces in Feldafing near Munich. I saw many interesting cipher exhibits, as well as a photograph of an encryption machine I had never heard of before. Can a reader help to find out more about this device?
A French magazine article reports on an encrypted diary written by a pedophile priest. The plaintext is not known to me. Can a reader break it?
In 2008 the magazine “The Canadian Philatelist” published an interesting article about encrypted postcards. Among other things, this article mentions a nice pigpen-enciphered postcard you can try to decipher.
A recent book mentions a cipher used by a German spy during the Second World War. Can you break a message I encrypted with this method?
A few years ago, German late-night show host Stefan Raab presented a number puzzle in his show “TV total”. It involves cryptography and should be easy to solve for readers of this blog.
In 1875 a German crypto book author published a cryptogram and promised to pay 100 Silvermarks to the first one who solved it. It’s probably to late now to win this prize, but I’m sure some of my readers are still interested in breaking this cryptogram.